Conventionally, in a lithography process for producing electronic devices (micro-devices) such as a liquid crystal display device or a semiconductor device (such as an integrated circuit), exposure apparatuses are used such as an exposure apparatus of a step-and-scan method (a so-called scanning stepper (also called a scanner)) that transfers a pattern formed on a mask irradiated with an energy beam, while a mask (photomask) or a reticle (hereinafter collectively called a “mask”) and a glass plate or a wafer (hereinafter collectively called a “substrate”) are moved synchronously along a predetermined scanning direction (scan direction).
As this type of exposure apparatus, an exposure apparatus equipped with an optical interferometer system is known that obtains position information within a horizontal plane of a substrate subject to exposure using a bar mirror (long mirror) that a substrate stage device has (for example, refer to PTL 1).
Here, in the case of obtaining position information of the substrate using the optical interferometer system, influence of the so-called air fluctuation cannot be ignored. While the influence of air fluctuation mentioned above can be reduced using an encoder system, due to the increasing size of substrates in recent years, it is becoming difficult to prepare a scale that can cover the entire moving range of the substrate.